(1) Field of the Invention
The invention relates to a method of metallization of an integrated circuit device, and more particularly, to a metallization method with improved interface area and interface mechanical properties in the manufacture of an integrated circuit device.
(2) Description of the Prior Art
In the fabrication of integrated circuit devices, metal layers make contact to lower conductive layers of the integrated circuit through vias in an insulating layer. Referring to FIG. 1, there is shown a contact of the prior art. A via or contact opening has been made through insulating layer 16 to lower conductive layer 14 on a semiconductor substrate. Top metal layer 20 contacts the top side of the bottom conductive layer 14. Some disadvantages of the conventional contact are the small interface area between the conductors and severe surface damage, residue, or contamination to the top side of the bottom conductive layer contacted by the top metal layer.
U.S. Pat. No. 5,231,053 to Bost et al shows etching a via hole into a trimetal layer and forming a tungsten plug within the via hole. U.S. Pat. No. 4,997,789 to Keller et al shows etching through an Aluminum layer, then filling the hole, and overlaying with tungsten.